QuestionI have a Chevrolet Astro 1988. After, let's say, 10kms from departure (cool engine), the light of "Service Engine Soon" goes light. If I stop 5-10 seconds it will not light again when I start engine. Why?
AnswerIt may just be getting a rich or lean signal for a longer period than it likes, and then correcting itself.
If the light goes off, then it isn't something that should cause you to park it.
Now, if it starts actually blinking, then there is something that you should get checked rather soon, but what you describe doesn't fit that.
That 10 Kms thing is because sensor readings are not even used till the temperature reaches normal operating temperature, which would take about that far.
At that time, the oxygen sensor may not be warmed up enough to give a truely accurate reading, thus the rich or lean reading.
Then after the oxygen sensor heats up and starts sending a more accurate reading, it clears up the problem.
That is just one possible scenario.
If the light ultimately ends up staying off after all warms up, I wouldn't be concerned.
Van
